The invention relates to equipment for dewatering and defibrating ligno-cellulose material using a screw.
Conventionally, screw presses or plug feeders have been used to dewater wood chips or other ligno-cellulose material. In these devices, the material is primarily compressed, during which process it is defibrated to some extent and dewatered. In order to achieve better dewatering, the material must be defibrated further, which is often achieved with two intermeshing double screws or single screw with discontinuous screw flights and shearing pins. Controlled defibrating is not possible on these machines; thus the dewatering capacity is also limited.